Dennis Had Inspire Amps

[Musica Amantem]

Hi Peter! I sent you a reply. Any suggestions, anyone?

[Bombadil]

Originally Posted by Musica Amantem

Hi Peter! I sent you a reply. Any suggestions, anyone?

Can't help you on this, as I hear little to no difference between rectifiers of the same type. I own two 274b and five 5U4GB, all different brands, and I interchange them on occasion just to listen for differences, but don't hear any. I hear significant differences between 6SN7 tubes and also my power tubes. Hear some differences (mostly in the deeper bass notes) between the 274b vs GZ34. So that ends up being the crux of my decision as to what rectifier to use: One of my GZ34s vs one of my 274b/5U4GBs.

[Musica Amantem]

Originally Posted by Bombadil

Can't help you on this, as I hear little to no difference between rectifiers of the same type. I own two 274b and five 5U4GB, all different brands, and I interchange them on occasion just to listen for differences, but don't hear any. I hear significant differences between 6SN7 tubes and also my power tubes. Hear some differences (mostly in the deeper bass notes) between the 274b vs GZ34. So that ends up being the crux of my decision as to what rectifier to use: One of my GZ34s vs one of my 274b/5U4GBs.

In my case, I do hear a difference across rectifier types, like my two best favorites, 274B and 5Z4, each one excelling with different output tubes, OTBE. The 5Z3 I had never cared for and the 5AR4, to me, is second best against the 5Z4, a little aggressive to my tastes (both with the KT-88 / KT-77). The most versatile rectifier due to its synergies with most of my preferred tubes, though, is the 274B (S.E., Mesh Plate), as it is never out of place and very versatile.

Detecting differences across brands of the same rectifier is something I can't do, as I only have one of each of all these types, so hard to tell. That is why I would prefer getting another 274B Mesh Plate from Sophia Electric but their price is too high for what these seem to last, in my experience just a small fraction of its advertised 5,000 hrs. Thanks for your thoughts.

[Bombadil]

Originally Posted by Musica Amantem

In my case, I do hear a difference across rectifier types, like my two best favorites, 274B and 5Z4, each one excelling with different output tubes, OTBE.

This is consistent with what I wrote. I said that I didn't hear differences within rectifier types. In this case a 274b vs a 5Z4 is comparing two dramatically different rectifiers. The maximum plate current of a 5Z4 is about half that of a 274b. And the voltage drop is less than half.

Using a 5Z4 will decrease your output wattage as compared to a 274b, 5U4GB, or GZ34/5AR4.

[Bombadil]

There are many good vintage 5U4GB tubes which can be had for less than $20, sometimes as low as $10. GE, JAN Philips, RCA, Sylvania, Tung-sol. I have 5 of them. Found a couple in surplus store tube boxes for $5 each. Another one in a big bag of tubes I purchased for $25. They are very common. And they seem to last forever.

I also have a new Genalex GZ34. This one set me back $33. Made in Russia. It's a nice tube which maximizes the output power and bass definition in my Inspire. I'm not certain it is any different than the current Sovtek or Tung-sol GZ34 tubes, as they are all made in Russia at the same plant and look identical.

The stock tube in my Inspire was a JJ GZ34. I guess it is okay but it is small and puny looking and, on the whole, I don't like JJ tubes. So I don't use it.

[Musica Amantem]

Originally Posted by Bombadil

This is consistent with what I wrote. I said that I didn't hear differences within rectifier types. In this case a 274b vs a 5Z4 is comparing two dramatically different rectifiers. The maximum plate current of a 5Z4 is about half that of a 274b. And the voltage drop is less than half.

Using a 5Z4 will decrease your output wattage as compared to a 274b, 5U4GB, or GZ34/5AR4.

Oh, I agree, I was just explaining what my experiences have been ... I would probably tell the difference only between mesh plate and rigid plate on the same rectifier.

[Musica Amantem]

Originally Posted by Bombadil

There are many good vintage 5U4GB tubes which can be had for less than $20, sometimes as low as $10. GE, JAN Philips, RCA, Sylvania, Tung-sol. I have 5 of them. Found a couple in surplus store tube boxes for $5 each. Another one in a big bag of tubes I purchased for $25. They are very common. And they seem to last forever.

I also have a new Genalex GZ34. This one set me back $33. Made in Russia. It's a nice tube which maximizes the output power and bass definition in my Inspire. I'm not certain it is any different than the current Sovtek or Tung-sol GZ34 tubes, as they are all made in Russia at the same plant and look identical.

The stock tube in my Inspire was a JJ GZ34. I guess it is okay but it is small and puny looking and, on the whole, I don't like JJ tubes. So I don't use it.

Agreed on Genalex being in general much preferred to JJ's as a brand. I rather use 5Z4 over the GZ34 with my KT-77's and KT-88's.

Do you like those vintage American-made NOS 274B (5U4G) rectifiers? My only experience has been with the RCA 5Z3 (I know, a different rectifier), and I really don't like it. But, at those prices it would not be a problem trying them. Of course, one has to be present in those tube patio sales to take advantage of those vintage opportunities, which is not an option for me. I'll be looking around for those then, thanks!

[BearCityUSA]

Originally Posted by Analog Addict

Oh yeah, before I forget, a certain radioman731 has put a brand new 2A3 amp up on E-bay for one lucky discerning consumer. Get it while it's hot!!!

There is a pair of inspire 2014 PSE 6v6 mono-blocks on e-Bay today. Great price. If I was in the market... but alas, I cannot justify. Trying to save for the tax man and maybe a set speakers if he doesn't take to much.

[Bombadil]

I wouldn't use a 5Z4 with KT88s. KT88s can handle the current and voltage of a GZ34 at 250 mA and 450V. A 5Z4 has only a 125 mA maximum and 350V. Way under powering a KT88.

I do like the vintage 5U4GBs. Many tube amp owners swear by them. The RCA Tall black plate one is pricey, around $100.

[Bombadil]

Those PSE 6V6 amps can run only 6V6s, correct? I haven't liked those output tubes in my KT88 SE Inspire.